MYSTERY OF THE MIRAGE.

Northland Age, Volume IV, Issue 42, 22 June 1908, Page 7

MYSTERY OF THE MIRAGE.

About that natural phenomenon, the mirage, much mystery clung in days of old ; bu£ science explains it as readily as the* rainbow.

A mirage may occur at any place where the denser stratum of air is placed above the lighter stratum, thus refracting the rays of light, the common surface of the two stratums acting as a mirror.

In looming mirages distant objects show an extravagant increase in vertical height without alteration in breadth. Distant hummocks office are thus magnified into immense towers and pinnacles, and a ship is sometimes abnormally drawn out, until it appears twelve or thirteen times as high as it is long. Rocks are seen drawn up to ten or twelve times their proper height. Houses, as well as human beings and animals, appear in like exaggerated shape.

Another form of mirage is when a ship or some other object near the water, seems greatly elongated, and a second inverted image meets it from above.

Sometimes the proper image of the object is elevated far above the sea, while the second image strangely appears inverted beneath it, the whole surrounded by a sheet of sky, which is mirrored and repeated within it.* l In 1882, in the Arctic region, Captain Scoresby recognised, by its inverted image in the air, his father’s ship, the Fame, which afterwards proved to be seventeen miles beyond the visible horizon of his observation.

One August evening in 1806 Dr. Vince saw from Ramsgate, at which place only the tops of Dover Castle towers are usually visible, the whole of the castle. It! appeared as though lifted up and bodily placed on the near side of the intervening 'hill. So perfect was this illusion that the hill itself actually could not be seen through the figure. Some forms of mirage are lateral as well as vertical, arising from unequal density of two contiguous vertical bodies of air. Thus, on Lake Geneva, a boat has been seen double, the t\po immages some distance apart Persons have been duplicated in the same way. Any one on a hot clay, by placing his eye near to a heated wall may see lateral mirages of objects at a distance, and nearly on a iline with the wall.

Mirages are very frequent on deserts or the large sandy plains which abound in the south-western States and Territories. Many a panting waggon-train has pushed on in joyous haste at the sight of a green grove or limpid lake, only tq be cruelly disappointed at the lading away of the vision. Is it any wonder that the natives and Indians regard the phenomenon as the work of evil and tantalizing spirits ? Lake Ontario is famous for beautiful and wonderful mirages, 'during which the opposite shore of the lake is plainly visible from either side.— i'Scraoß.”